Edward Redman, 18, (pictured left) is seen joking with a pal on the back of a bus but then he covers his mouth as he reads a text message saying his victim, Jay Whiston, 17, had died

Edward Redman, 18, can be seen joking with a pal on the back of the bus but then his expression changes as he looks at his mobile.

An hour and a half earlier he had stabbed Jay Whiston, 17, in the heart but did not know until that point that he had murdered him.

He was jailed last month for 17 years for the killing and the CCTV footage was released after Rhys Hennebry, 19, was jailed for three years for his involvement in the death.

At an earlier hearing Redman's father Gary and brother John were also jailed for two years for destroying evidence linked to the murder, and his former girlfriend, Shannon Fenlon, was sent to a young offenders' institution for nine months.

Redman and Hennebry fled from a party in Colchester, Essex, after the stabbing of Jay Whiston, 17.

Essex Police

Edward Redman faces a minimum 17 years in jail for murder at out-of-control Facebook party

Redman can be seen putting his hand over his mouth in shock as he reads a text message.

Police believe this is the moment when Redman finds out he is a murderer.

In the minutes that follow he can be seen making a series of frantic phone calls and text messages.

They are caught running for a bus, about 90 minutes later, just after 11.30pm.

After getting on, Redman receives a message and the pair move to the back.

He shows Hennebry the message and Redman puts his hand over his mouth in shock.

These messages and calls were later deleted and Redman's clothes and the murder weapon disappeared, with the help of his father, brother and then girlfriend.

The footage was released after Hennebry was yesterday locked up for his role in Jay's murder.

PA

Hero Jay Whiston 17, of Clacton, Essex, who was murdered after sticking up for a friend

He was sent to a young offenders' institution for three years on two charges of affray.

Chelmsford Crown Court heard how Hennebry attacked Dan Richman on Friday, September 7, 2012. Mr Richman was confronted on the doorstep of his then girlfriend's home in St Andrew's Avenue by Hennebry and three other men.

He was was kicked on the ground by three of the men, while a fourth stood nearby holding a knife. The attack lasted for about a minute before all four then ran off.

The next night, Hennebry went to the house party in Lexden, where Jay met his death.

As Jay and his friends walked down an alleyway at the side of the house, Edward Redman, Hennebry and others were coming the other way.

Redman asked one of Jay's friends for a drink from a bottle of whiskey he had but when the teenager said no, Redman hit him.

In the fight that followed, Redman stabbed Jay twice - once through the heart.

As he staggered from the scene, Hennebry was heard to say "I'm going to bottle him" and threw a bottle towards Jay, and Redman stabbed Jay a second time in the abdomen.

As they fled from the scene, others heard them saying "let's get out of here" and "we'll stick together through this."

Hennebry admitted a charge of affray in connection with Jay's death before the trial of Redman. He could not be named during the case for legal reasons.

Sentencing Hennebry yesterday, Judge Charles Gratwicke told him: "At the time, it is clear you and others involved were totally out of control on the streets of Colchester.

"You were a violent and dangerous man."

The judge said he accepted Hennebry did not know Redman was carrying a knife and was going to use it.

But he added: "You played a substantial part in this incident and you were clearly at the time a violent young man."

Hennebry bragged on Facebook how he would be locked up and only serve half the time.

On Monday, the day before Hennebry was sentenced, there were posts on his account saying "jail tomorrow wooo woooop" and "three-and-a-half to four years, do half, so like two years f**** it."

Jay's mum Caroline Shearer, who was in court for the sentencing, said: "I am totally disappointed with this sentence, to actually go and take a bottle of beer and smash it over someone's head before his friend stabbed him to death, and then get two years is laughable."

Jay's family is planning to appeal for the sentence to be increased so Hennebry is given the maximum three-year term for each of the crimes.